462 research outputs found

    Measurement of the tensor analyzing power T20 in the dd->^3Hen and dd->^3Hp at intermediate energies and at zero degree

    Get PDF
    The data on the tensor analyzing power T20 in the dd->^3Hen and dd-> ^3Hp reactions at 140, 200 and 270 MeV of the deuteron kinetic energy and at zero degree obtained at RIKEN Accelerator Research Facility are presented. The observed positive sign of T20 clearly demonstrates the sensitivity to the D/S wave ratios in the ^3He and ^3H in the energy domain of the measurements. The T20 data for the ^3He-n and ^3H-p channels are in agreement within experimental accuracy.Comment: 9 pages, 3 figures, submitted in Phys.Lett.

    Reaction mechanism and characteristics of T_{20} in d + ^3He backward elastic scattering at intermediate energies

    Get PDF
    For backward elastic scattering of deuterons by ^3He, cross sections \sigma and tensor analyzing power T_{20} are measured at E_d=140-270 MeV. The data are analyzed by the PWIA and by the general formula which includes virtual excitations of other channels, with the assumption of the proton transfer from ^3He to the deuteron. Using ^3He wave functions calculated by the Faddeev equation, the PWIA describes global features of the experimental data, while the virtual excitation effects are important for quantitative fits to the T_{20} data. Theoretical predictions on T_{20}, K_y^y (polarization transfer coefficient) and C_{yy} (spin correlation coefficient) are provided up to GeV energies.Comment: REVTEX+epsfig, 17 pages including 6 eps figs, to be published in Phys. Rev.

    Scaling study of the pion electroproduction cross sections and the pion form factor

    Full text link
    The 1^{1}H(e,eπ+e,e^\prime \pi^+)n cross section was measured for a range of four-momentum transfer up to Q2Q^2=3.91 GeV2^2 at values of the invariant mass, WW, above the resonance region. The Q2Q^2-dependence of the longitudinal component is consistent with the Q2Q^2-scaling prediction for hard exclusive processes. This suggests that perturbative QCD concepts are applicable at rather low values of Q2Q^2. Pion form factor results, while consistent with the Q2Q^2-scaling prediction, are inconsistent in magnitude with perturbative QCD calculations. The extraction of Generalized Parton Distributions from hard exclusive processes assumes the dominance of the longitudinal term. However, transverse contributions to the cross section are still significant at Q2Q^2=3.91 GeV2^2.Comment: 6 pages, 3 figure

    Nuclear transparency and effective kaon-nucleon cross section from the A(e, e'K+) reaction

    Full text link
    We have determined the transparency of the nuclear medium to kaons from A(e,eK+)A(e,e^{'} K^{+}) measurements on 12^{12}C, 63^{63}Cu, and 197^{197}Au targets. The measurements were performed at the Jefferson Laboratory and span a range in four-momentum-transfer squared Q2^2=1.1 -- 3.0 GeV2^2. The nuclear transparency was defined as the ratio of measured kaon electroproduction cross sections with respect to deuterium, (σA/σD\sigma^{A}/\sigma^{D}). We further extracted the atomic number (AA) dependence of the transparency as parametrized by T=(A/2)α1T= (A/2)^{\alpha-1} and, within a simple model assumption, the in-medium effective kaon-nucleon cross sections. The effective cross sections extracted from the electroproduction data are found to be smaller than the free cross sections determined from kaon-nucleon scattering experiments, and the parameter α\alpha was found to be significantly larger than those obtained from kaon-nucleus scattering. We have included similar comparisons between pion- and proton-nucleon effective cross sections as determined from electron scattering experiments, and pion-nucleus and proton-nucleus scattering data.Comment: 7 pages, 5 figure

    Study of the A(e,e'π+\pi^+) Reaction on 1^1H, 2^2H, 12^{12}C, 27^{27}Al, 63^{63}Cu and 197^{197}Au

    Full text link
    Cross sections for the p(e,eπ+e,e'\pi^{+})n process on 1^1H, 2^2H, 12^{12}C, 27^{27}Al, 63^{63}Cu and 197^{197}Au targets were measured at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) in order to extract the nuclear transparencies. Data were taken for four-momentum transfers ranging from Q2Q^2=1.1 to 4.8 GeV2^2 for a fixed center of mass energy of WW=2.14 GeV. The ratio of σL\sigma_L and σT\sigma_T was extracted from the measured cross sections for 1^1H, 2^2H, 12^{12}C and 63^{63}Cu targets at Q2Q^2 = 2.15 and 4.0 GeV2^2 allowing for additional studies of the reaction mechanism. The experimental setup and the analysis of the data are described in detail including systematic studies needed to obtain the results. The results for the nuclear transparency and the differential cross sections as a function of the pion momentum at the different values of Q2Q^2 are presented. Global features of the data are discussed and the data are compared with the results of model calculations for the p(e,eπ+e,e'\pi^{+})n reaction from nuclear targets.Comment: 28 pages, 19 figures, submited to PR

    Measurement of Nuclear Transparency for the A(e,e' pi^+) Reaction

    Full text link
    We have measured the nuclear transparency of the A(e,e' pi^+) process in ^{2}H,^{12}C, ^{27}Al, ^{63}Cu and ^{197}Au targets. These measurements were performed at the Jefferson Laboratory over a four momentum transfer squared range Q^2 = 1.1 - 4.7 (GeV/c)^2. The nuclear transparency was extracted as the super-ratio of (σA/σH)(\sigma_A/\sigma_H) from data to a model of pion-electroproduction from nuclei without pi-N final state interactions. The Q^2 and atomic number dependence of the nuclear transparency both show deviations from traditional nuclear physics expectations, and are consistent with calculations that include the quantum chromodynamical phenomenon of color transparency.Comment: 5 pages, 3 figs Changes to figure 2 and 3 (error band updated and theory curves updated

    Scaling of the F_2 structure function in nuclei and quark distributions at x>1

    Full text link
    We present new data on electron scattering from a range of nuclei taken in Hall C at Jefferson Lab. For heavy nuclei, we observe a rapid falloff in the cross section for x>1x>1, which is sensitive to short range contributions to the nuclear wave-function, and in deep inelastic scattering corresponds to probing extremely high momentum quarks. This result agrees with higher energy muon scattering measurements, but is in sharp contrast to neutrino scattering measurements which suggested a dramatic enhancement in the distribution of the `super-fast' quarks probed at x>1. The falloff at x>1 is noticeably stronger in ^2H and ^3He, but nearly identical for all heavier nuclei.Comment: 5 pages, 4 figures, to be submitted to physical revie

    Association between Insomnia Symptoms and Hemoglobin A1c Level in Japanese Men

    Get PDF
    Background: The evidence for an association between insomnia symptoms and blood hemoglobin A1c (HbA1c) level has been limited and inconclusive. The aim of this study was to assess whether each symptom of initial, middle, and terminal insomnia influences HbA 1c level in Japanese men. Methods: This cross-sectional study examined 1,022 male workers aged 22–69 years with no history of diabetes at a Japanese company’s annual health check-up in April 2010. High HbA1c was defined as a blood level of HbA1c $6.0%. Three types of insomnia symptoms (i.e., difficulty in initiating sleep, difficulty in maintaining sleep, and early morning awakening) from the previous month were assessed by 3 responses (i.e., lasting more than 2 weeks, sometimes, and seldom or never [reference group]). Results: The overall prevalence of high HbA1c was 5.2%. High HbA1c was positively and linearly associated with both difficulty in maintaining sleep (P for trend =.002) and early morning awakening (P for trend =.007). More specifically, after adjusting for potential confounding factors, high HbA1c was significantly associated with difficulty in maintaining sleep lasting more than 2 weeks (adjusted odds ratio, 6.79 [95 % confidence interval, 1.86–24.85]) or sometimes (2.33 [1.19–4.55]). High HbA1c was also significantly associated with early morning awakening lasting more than 2 weeks (3.96 [1.24–12.59]). Conclusion: Insomnia symptoms, particularly difficulty in maintaining sleep and early morning awakening, were found t
    corecore